The liquid crystal display is used increasingly for television, PC, etc. in ordinary homes. A Braun tube (CRT: cathode ray tube) display which provides high-definition images is still used in many situations in the fields where the image quality is valued for monitors typically used as the master monitors in broadcasting stations and the monitors used at video creation spots. Even in the same field, it is considered to use a liquid crystal display or a PDP (Plasma Display Panel) instead of the CRT display, but the image quality of the liquid crystal display or the PDP is not satisfactory yet in comparison with that of the CRT display although the improvement of the image quality is underway. In view of the above circumstances, an image display device other than the CRT display has not been used positively in the above-described fields of broadcasting and the like.
The broadcasting color CRT reproduces the shape, movement and color phase of an image subject on an image-receiving screen through imaging (color camera), transmitting and image-receiving processes. Therefore, a method of transmitting an image signal including the color phase is standardized. Typical ones of the standards are the standard defined by NTSC (National Television System Committee), and the standard defined by EBU (European Broadcasting Union).
The EBU standard equivalent to 72% of the NTSC (international standard showing an ideal color reproduction range) which can be displayed by the CRT is used as a standard in the broadcasting and other fields and being still in use. Accordingly, it is now being attempted to obtain the same image quality as that of the CRT display by designing the liquid crystal display device so as to conform to the EBU standard being used in the fields of broadcasting and the like. And developments have been made on color filters, backlights and the like having good color reproducibility conforming to the EBU standard to realize the above.
The color reproducibility of the liquid crystal display device is determined by a combination of the backlight and the color filter. Several color filters have been developed to obtain color reproducibility conforming to the EBU standard, but no backlight for the liquid crystal display device has been obtained to realize the color reproducibility conforming to the EBU standard by combining with the above color filters.